Various different methods and apparatus for measurement of area have been proposed in the prior art. One such prior proposal involves moving the skin through a measuring apparatus which includes a plurality of photoelectric sensing devices which are arranged in a row which is transverse to the direction of movement of the skin so that as the skin moves through the apparatus, the device measures successive widths of the skin. The successive widths are integrated in a summing device so as to give a measure of the area. Such a method is disclosed in U.K. Pat. Specification No. 1,028,194. U.K. Pat. Specification Nos. 1,317,728, 1,165,227 and 922,545 each disclose a similar apparatus and method, but optical fibres are employed in a manner which makes it possible to employ a single photoelectric sensing device instead of the aforementioned plurality.
Whilst the abovementioned prior proposals may be satisfactory in many situations, a problem arises when the area of sheepskin is to be measured while the wool is still attached to the pelt. The problem is that it is the area of the pelt which is required to be measured, but the wool extends beyond the edges of the pelt with the result that, since photoelectric sensing devices cannot distinguish between the pelt and the wool, an erroneous measure of the area would be obtained. The invention aims to provide a method and apparatus in which this problem does not arise.